Fractures in hull pre-existed sinking of Tom Bussler in Tennessee River: US NTB

There were apparently pre-existing fractures in the hull of towing vessel Tom Bussler, which sank on January 7th 2019 while transiting upbound on the Tennessee River near Calvert City, Kentucky, according to an accident report from the US National Transportation Board (NTB)

The Tom Bussler was transiting in light boat condition upbound on the Tennessee River at mile 15 near Calvert City, Kentucky when the vessel began flooding and quickly sank in the channel. Both crewmembers aboard abandoned the vessel into the river and were rescued by a Good Samaritan vessel. No pollution or injuries were reported.

Damage to the vessel was estimated at $297,368, and it was scrapped.

On January 19th, 12 days after the incident,  the vessel was drydocked, and a marine surveyor inspected the vessel for damages. The surveyor noted several fractures at multiple points in the hull that appeared to “pre-exist the incident.”

The upper 12 inches of the port bow corner plating contained an approximate total of 30 inches of fractures, and the starboard bow corner plating contained an 18-inch fracture, all open to a width of 0.25 inch.

On the inboard sides of both the port and starboard towknees, the forward extreme of the bow deck plating of each contained a 12-inch transfer fracture open to 0.25 inch.

There were also fractures at the base of the headlog plating just starboard of centreline, in the hull bottom plating at a point adjacent to the inboard side of the starboard inboard fair water angle, and in the hull bottom plating inboard from the inboard leg of the port strut.

The surveyor also noted that “the lower [5ft] of the shredded tire bumper on the starboard towknee was adrift and partially missing.”

The vessel was built in 1968, and the investigation found that probable cause of the flooding was the company’s lack of an effective hull maintenance and repair programme, which resulted in flooding into the bow voids and engine room through fractures in the hull.

Based on the numerous cracks in the Tom Bussler’s hull found during the post-accident survey, and the documented reports from the crew of water leaking into voids, investigators attempted to determine how long the watertight integrity issues had existed and what actions, if any, had been taken to mitigate them. The vessel had last been drydocked in January 2018, about a year before the accident. No hull repairs related to watertight integrity were scheduled or completed. Throughout 2018, multiple issues with the hull were reported by crewmembers. However, attempts to find the leaks were unsuccessful, and the reported issues were not resolved.

When the vessel was pushing a barge ahead, her bow was protected from the bow wave by the barge ahead, and the pre-existing fractures in the hull therefore remained above the effective waterline. However, at the time of the accident, the vessel was under way in light boat condition, without a barge to deflect water, and the bow therefore was subject to the water build up as it moved through the river.

Environmental damage included about 25 gallons diesel being released and oil sheen on water